578 DR. p. E. BEDDAED ON 



monograph, since there is some little variation in the characters 

 of the numerous examples which I have to consider here, which 

 variations do not militate against the exclusion of /. hyracis and 

 /. settii^ though they render difficult the distinguishing of my 

 species from some of the others referred to by Janicki. Thus 

 two examples measured only 68 mm. and 75 mm. respectively, 

 and one of them was quite 3 mm. in diameter at the widest part. 

 The segments were never longer than broad, except perhaps a 

 trifle longer in the thin anterioi- region of the body. They 

 varied somewhat in relative dimensions, as is the case * with 

 those of /. hyracis. Occasionally the unilateral genital pores were 

 very visible on slight papillae near to the hinder end of segments. 



The scolex is quite unai-med and conspicuous by its size, as 

 already mentioned. It is usually more or less globular in form, 

 with a slightly prominent and somewhat pointed apex, as is 

 shown in Janicki's figure of /. settii'f, and which is, of course, 

 the rostellar region. Occasionally, however, this apical region 

 does not protrude, but is represented by a depression on the 

 surface. The scolex is, moreover, sometimes flattened in its 

 entirety from above downwards, and presents a mushroom-like 

 appearance, the edges of the disc projecting round the neck, 

 which thus presents the appearance of the stalk of the 

 mushroom. 



Longitudinal sections through the scolex confirm the total 

 absence of hooks or of any trace of a rostellum, save the slight 

 projection already mentioned. Nor could I detect anything 

 peculiar in the structure of the suckers, which, according to 

 Janicki and others, are remarkable for a funnel-like ingrowth 

 leading to the actual sucker, which thus lies at the bottom of 

 a depression. It is true that in the present species, as in many 

 tapeworms of the group Tetracotylea which I have examined, 

 the sucker does not lie externally on the scolex, but is covered by 

 an outer layer of body-wall which is only interrupted at the 

 orifice of the sucker. The free edge of this, when depressed 

 towards the interior of the sucker, is doubtless funnel-shaped 

 and would give rise to the appearances represented by Janicki. 

 Perhaps, however, there is some divergence from the normal 

 condition of the suckers in the members of the genus I'eferred 

 to by him, which I certainly have not found in the species 

 with which I am at present concerned. The direction of the 

 suckers seems to me to vary somewhat ; generally they are 

 lateral, but sometimes with a forward inclination. 



It has been already observed that in this genus water- vessels 

 of unusual width extend far into the head. Such are figured by 

 Janicki, and referred to by Pagenstecher $ (quoted by Janicki §) 

 as " einen mit Ringmuskeln umspinnenen Wasserbehalter." In 



* Janicki, loc. cit. pi. xii. figs. 2-5. 

 t Loc. cit. pi. xii. fig. 10. 

 t Zeitschr. f. wiss. Zool. Bd. xxx. 1878. 

 § Loc. cit. p. 389. 



